Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: Sanding fiberglass

Posted by nvaccaro on 01/20/09 - 5:29 PM
#1

Hello everyone,

I have been restoring my '81 Montauk since before Christmas. I had posted earlier that the previous owner had tried to paint the bottom of the boat and then about 2 inches up the sides.

I bought a product from West Marine that has done well to remove most of the paint. A second coat is probably necessary.

Where the funky blue paint has been removed, the fiberglass is nice and clean looking.(Looks new). The sides above this old paint line look dingy and stained.

I have tried 3M rubbing compund and 3M wax. Neither worked. Should I try wet sanding the fiberglass? If so, what exactly is involved with this process?

Another thought is maybe their is some other product directly made for such a problem. I would appreciate any insight you guys could offer.

Posted by todd12 on 01/20/09 - 5:58 PM
#2

Try wetsanding with 400 grit sand paper then comback with 3M compound and high speed buff.


Todd

Posted by nvaccaro on 01/20/09 - 6:14 PM
#3

Thanks, Todd.

I'll give it a shot.

Posted by kamie on 01/20/09 - 7:08 PM
#4

There is no need to start at 400, I would start at 800 on a patch and see how it sands out. You also need to do more than one grit of sandpaper, the idea is that finer grits take out the scratches made by the courser ones. You should wet sand up to 1000/1200 grit if you can find it, then switch to Mequiars #44 Fiberglass restorer, Finesse-it and finally a good wax. Your hull should shine like new.

Posted by Barryg on 01/20/09 - 7:19 PM
#5

Starbrite Hull CLeaner does a great job on stains. BG

Posted by Binkie on 01/21/09 - 5:43 AM
#6

Follow kamie`s instructions. The finer the sandpaper you end up with the better the finish. You could go up to 2000 grit finish at the end. Its a time consuming process, but the results will be worth it. It is still a lot easier than re gel coating the hull. Just using 400 grit will not do the job.
Remember as in all endeavors, "Effort = Results"

rich

Posted by Guts on 01/21/09 - 7:47 AM
#7

I would like to but my two cents in. I have been power puffing my BW. A thread I read some where said do not be afraid to sand then puff. After removing the decals and puffing the side you could still see where the BW decals were. I tried 400,600,800, and 1000. not good enough had to start with 220,then 320,working my way up to 1000. then I puffed the area again, after which I could still see some scratches here and there. I went to the 800, then to 1000. and puffed again. Just like new with out the logo BW. Now ready for new BW decals. Note here I had Janis cut the boat registration numbers out of the same color as the BW logo. MY Point don't be afraid to sand the gel coat it is thicker than you think... not like car paint. If a stain remover will work, it might be worth a try. It just might save you a lot of work sanding.
One more thing... If you have a hard time finding the really fine sand paper? look for a auto body supplier they will have it. 1000 in most cases is the highest I think you will need. and some heavy duty cleaner/compound.

Posted by kamie on 01/21/09 - 6:00 PM
#8

Since you have tried rubbing compound without success I would do one of the following

option 1:
Try Buff Magic. It is a rubbing compound like material that you work with a buffer. The key to getting the product to work correctly is to buff the area until the product is gone. Here is an older thread with photos of some trials I did on my 13 footer.
Non-Skid

If that works, then finish with color restore, finessit II and wax.

If that doesn't work

Option 2:
wet sanding the hull. Start with 600/800 grit, do a small 2 by 2 section. You want to sand off the stains and oxidation back to a uniform color. I would start with 800, 400 will get you to the color faster, but you will need to sand out the scratches with finer and finer sandpaper. Do a test, if you sand with the 800 and you don't seem to be making a difference, then drop back in grit but remember you will need to sand thru that many more grits for a finished product. The idea is the next finer grit sand out the scratches from the grit before. You do need to sand to 1000/1200 and then you can use buff magic if you have it from option 1 that didn't work or rubbing compound. 1000/1200 will get you a pretty shiny hull, but if you look closely there will still be tiny scratches. Then finish with a color restorer (really mild rubbing compound) and finally with wax. Do a small area with one grit, then move around the boat before you switch to the next finer grit. Wet sanding the hull is time consuming and a balancing act between taking off enough to get back to the correct color and taking of too much. All the products remove gelcoat that at best is ~ 20mils thick, which really isn't a very thick surface to start with.

good luck